[PATCH v2 1/2] util/main-loop: Fix maximum number of wait objects for win32

[Bin Meng]

From: Bin Meng <bin.meng@windriver.com>

The maximum number of wait objects for win32 should be
MAXIMUM_WAIT_OBJECTS, not MAXIMUM_WAIT_OBJECTS + 1.

Fix the logic in qemu_add_wait_object() to avoid adding
the same HANDLE twice.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
---

Changes in v2:
- fix the logic in qemu_add_wait_object() to avoid adding
  the same HANDLE twice

 util/main-loop.c | 43 +++++++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 12 deletions(-)

diff --git a/util/main-loop.c b/util/main-loop.c
index f00a25451b..66b2ae2800 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -363,37 +363,56 @@ void qemu_del_polling_cb(PollingFunc *func, void *opaque)
 /* Wait objects support */
 typedef struct WaitObjects {
     int num;
-    int revents[MAXIMUM_WAIT_OBJECTS + 1];
-    HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
-    WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
-    void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
+    int revents[MAXIMUM_WAIT_OBJECTS];
+    HANDLE events[MAXIMUM_WAIT_OBJECTS];
+    WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS];
+    void *opaque[MAXIMUM_WAIT_OBJECTS];
 } WaitObjects;
 
 static WaitObjects wait_objects = {0};
 
 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 {
+    int i;
+    bool found = false;
     WaitObjects *w = &wait_objects;
+
     if (w->num >= MAXIMUM_WAIT_OBJECTS) {
         return -1;
     }
-    w->events[w->num] = handle;
-    w->func[w->num] = func;
-    w->opaque[w->num] = opaque;
-    w->revents[w->num] = 0;
-    w->num++;
+
+    for (i = 0; i < w->num; i++) {
+        /* if the same handle is added twice, newer overwrites older */
+        if (w->events[i] == handle) {
+            found = true;
+            break;
+        }
+    }
+
+    w->events[i] = handle;
+    w->func[i] = func;
+    w->opaque[i] = opaque;
+    w->revents[i] = 0;
+
+    if (!found) {
+        w->num++;
+    }
+
     return 0;
 }
 
 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 {
-    int i, found;
+    int i;
+    bool found = false;
     WaitObjects *w = &wait_objects;
 
-    found = 0;
     for (i = 0; i < w->num; i++) {
         if (w->events[i] == handle) {
-            found = 1;
+            found = true;
+        }
+        if (i == MAXIMUM_WAIT_OBJECTS - 1) {
+            break;
         }
         if (found) {
             w->events[i] = w->events[i + 1];
-- 
2.34.1